The grown-up former Disney star put her concert series on hold weeks ago after checking into the hospital. She resumed the tour in London at the city's O2 Arena on Tuesday, May 6.

At the time of her hospitalization, Cyrus and her reps explained that she required treatment because of an "extreme allergic reaction" to the antibiotic Cephalexin, which was prescribed in order to treat a sinus infection.

"I didn't have a drug overdose," Cyrus said Tuesday, shooting down rumors that the allergic reaction was just an excuse. "I took some sh---y antibiotics that a doctor gave me for a sinus infection and I had a reaction."

The "We Can't Stop" singer, who performed her last show before the London gig on April 13, went on to add, "You have no idea how ready I am. There is nothing I would rather not do than lay in a bed for two weeks. It was the most miserable two weeks of my life."

Cyrus, who said she doesn't drink or smoke before a show because of how seriously she takes it, returned to the tour with a bang on Tuesday evening. She played to a packed crowd at the O2, and is set to hit big cities including Dublin, Stockholm, and Copenhagen in the coming weeks.